"Positioned at rest, the wings, and their straight and parallel dark lines occurring along the whole forewings and hind wing apices, must have produced a tongue-like shape covered with multiple, longitudinal, continuous lines, concealing the abdomen," says the paper.

These adaptive features helped the insects to conceal themselves within the similar tongue-shaped leaves or foliage of Membranifolia admirabilis, a relative of the ginkgo plant found in the area.

"The leaf-shaped plant organ from the contemporaneous ‘gymnosperm’ Membranifolia admirabilis was used as model for crypsis," say researchers.

Concealment in this case was probably used to escape small insect-eating birds and mammals that were thought to exist in the same biota.

Named Cretophasmomima melanogramma to refer to the coloration and patterns on its wings, this new species represents the oldest known fossil remains of stick insect. The female specimen found was about 2.2 inches long and the male specimens were slightly smaller (about 1.8 to 2 inches long). The world's longest insect, or Chan's Megastick, is a 22.3 inches long Malaysian variety of stick insect.